To continue the causes of variablility in AHH activities revealed in five subjects during the previous reporting period. To establish a monocyte cell culture system & compare results in this system with lymphocyte culture system used during the previous reporting period (30 donors, 3 samples each). To compare AHH activity in vitro with oxidation rates of certain drugs in vivo in 30 human male subjects age 18-35. To develop ways to improve culture quality for lymphocytes from lung cancer patients.